/**
 * Copyright (c) 2015-2020, wss 王山山
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.wss.utils;

import java.util.Objects;

import com.wss.utils.annotations.NotNull;

public final class StringUtil {
	
	public static boolean isEmpty(String str) {
		return (str == null) || str.length() == 0;
	}
	
	public static boolean isNotEmpty(String str) {
		return !isEmpty(str);
	}
	
	public static boolean isBlank(String str) {
		return (str == null) || str.trim().length() == 0;
	}
	
	public static boolean isNotBlank(String str) {
		return !isBlank(str);
	}
	
	public static String subtractSuffix(@NotNull String str, @NotNull String suffix) {
		Objects.requireNonNull(str);
		
		if (str.endsWith(suffix)) {
			int index = str.lastIndexOf(suffix);
			return str.substring(0, index);
		}
		return str;
	}
	
	public static String firstLetterLowerCase(@NotNull String str) {
		char ch = str.charAt(0);
		if (ch >= 'A' && ch <= 'Z') {
			ch += 32;
			char[] chs = str.toCharArray();
			chs[0] = ch;
			return new String(chs);
		}
		return str;
	}
}
